- Mar 4, 2019
While Gears of War 4 was The Coalition’s first game in the long-running franchise, it wasn’t until the developer’s second installment, Gears 5, that the studio was able to effectively make it their own. Interviewing several members from the Vancouver, Canada-based company, they talk about how Gears of War 4 allowed them to lay the foundation to achieve Gears 5’s monumental goals, which improves upon its predecessors with refined graphics, new open-world sections, revamped AI, and more. The culmination of their hard work has resulted in great reviews and one of the best looking games made yet.
We caught up with the studio to discuss how they leveraged Unreal and source-code access to deliver best-in-class post-processing effects, particles, and volumetric lighting while achieving 60 fps on the Xbox One X. Speaking to how they achieved smooth and consistent performance across a wide variety of hardware platforms, they share how they elegantly leveraged tools like HLOD to allow more draw calls, which enabled them to develop the game’s highly detailed and diverse environments.
Considering Gears 5 features some of the highest fidelity character models seen in a game to date, we also discuss how they used dual lobe specularity, backscattering, and sophisticated eye rendering features coupled with leading animation techniques to deliver highly believable digital humans. The Coalition also discuss some of the challenges they faced developing the game’s open-world segments, which are new to the franchise, and explain how they overcame these hurdles.
Watch "The Visual Technology of Gears 5" presentation from Unreal Dev Days 2019.
With this being The Coalition’s second Gears game, how has development changed with Gears 5 compared to Gears of War 4?
Campaign Design Director Matt Searcy: Gears of War 4 was really focused on proving we could make a great Gears game. It was important to us that fans saw The Coalition carrying the torch for the world, characters, and gameplay. A lot of our focus on that game was around gameplay hitting parity with Gears [of War] 3 (with a few tweaks) and developing new Gears combat, enemies, and modes around that core experience.
In that sense, Gears of War 4 was really pre-production for Gears 5. We had confidence in our ability to make a great Gears game, and from the reviews and feedback we received, it was clear we hit that goal, and that the community wanted to see it pushed further.
On Gears 5, we started with a directive to challenge expectations. It still needed to feel like a great Gears game, but our pre-production was focused on exploring new experiences and how they could fit with Gears. Features like Jack, the Skiff, and Escape pushed the design of the game to new places, while other disciplines were able to invest in new techniques and technology from the start. Without the foundation and expertise we developed on Gears of War 4, we could never have explored these in the time we had.
Gears 5 features an impressive array of visual effects that include per-object motion blur, screen space reflections, sophisticated depth-of-field effects, tessellation, and more. How did the team employ the elegant use of these post-process effects?
Studio Technical Art Director Colin Penty:We employed these post-process effects very tactfully as we didn't want to compromise visual quality but still wanted to maintain 60 fps on Xbox One X. We integrated all the post-process effects we could from Epic's latest UE4 release into our own version of the UE4 engine, with the new Diaphragm DOF being the last post-process integration we did.
In terms of how we used these post-process effects, we generally used the non-glossy high quality SSR in campaign wherever we could afford it on Xbox One (PC does glossy SSR). For tessellation, we had our own custom async tessellation shader we created that we used almost exclusively on our snow and sand Materials. If you want to deform sand and snow dynamically around the player, tessellation is almost required to do that realistically unless you've pre-tessellated your mesh extremely high. Bloomwas used liberally throughout the game, though we generally tried to avoid the tightest Bloom kernel as that one is quite expensive on GPU performance. We incorporated more camera exposure swing than Gears of War 4, allowing the camera to adjust to bright and dark areas of the map, though again being mindful of performance if we had areas of the game that didn't have a wide range of lighting values, we would lock the camera exposure to improve performance. Finally, we did a tuning pass across the game near the end for lens flaresand lens dirt.
We also set up our post-process chain to run asynchronously over the next frame, which allowed us to claw some performance back. This made a lot of sense given our post-processing pass was quite expensive due to always outputting at native resolution. We leaned on UE4's temporal upscaling to scale the internal resolution of our base pass/lighting/translucency/etc. to maintain GPU performance.
Gears 5 uses impressive lighting with volumetric lights and fog coupled with dynamic shadows. How did the team incorporate this?
Penty: Our team was a big fan of the Volumetric Fog system added to UE4 and used it wherever we could. We created a Blueprints system that allowed us to place volume fog primitives throughout the level, which we will be discussing more in-depth at GDC 2020. I'm proud of the volume fog quality we were able to achieve in the campaign while maintaining 60 fps on Xbox One X.
For lighting, we made the decision to get away from using stationary lights, which we used a lot of on Gears of War 4. This allowed us to stop using shadow map textures for shadows saving us texture memory, speeding up our shader rendering, and allowed us to have full real-time shadows. We instead used Moveable Lights for all of our lights in the game, with a small tweak where we allowed Moveable Lights to bake out indirect data using Lightmass. This all gets stored in our lightmaps, which are different than shadow maps in that they store all the color GI data, not shadows.
Beyond our Directional Light shadow cascades, we used distance field ray traced shadows to shadow the environment. This is where the lighting system used a distance field representation of the mesh as the shadow caster. Since this was only seen in the distance for us, we could afford to have the distance field representation not be super accurate to save some memory.
Of course, it takes a talented lighting team to pull together all these technical elements and deliver some great looking visuals, which our team did an amazing job of.
The game features fantastic particle effects. How did The Coalition deliver on this front?
Penty: Our VFX team delivered some amazing effects on Gears 5. This was especially challenging as consoles don't have the strongest CPUs, and VFX can really be taxing on a CPU. To get around this limitation, we created a new VFX system using the Material Editor called Swift Particles that allowed us to create VFX using vertex offsets in a shader that didn't have any CPU overhead. We primarily used Swift Particles for environmental VFX [such] as snow, dust, and rain.
We made use of GPU particles wherever we could as well, though for certain more complicated effects, that was difficult to pull off. We added a "GPU Spawn" ability to UE4's particles that would allow the particles to spawn on the GPU as well.
To keep our CPU performance in-check, our tech art team spent a lot of time working with VFX to ensure the particle counts and emitter counts were reasonable while also making sure we used Particle LODs. We essentially had to go back through our Gears of War 4 character and weapon VFX and re-optimize everything for Gears 5 as Gears of War 4 was a 30 fps game.
The character faces in Gears 5 are fantastic with elegant uses of subsurface scattering and dual lobe specularity. Increasing fidelity even further, eyes also feature realistic light scattering. How did The Coalition manage to create the game’s beautiful digital human faces?
Penty: Our character rendering and performance is probably one of the larger visual jumps over Gears of War 4. Once development on Gears 5 began, we immediately went to work on our character skin, eyes, and hair.
For our skin, we implemented dual lobe specularity like you mentioned, which greatly improved the quality of our skin "sheen." We also refined our skin backscattering using photographic reference for ground truth. We added detail normals for pore detail as well.
For the hair, we created a better tool for generating hair AO using Houdini Engine in Maya to better ground the hair. We did some tuning of the hair Material but kept the shading model the same for the hair as what Gears of War 4 used, which was a Disney Marschner shading model.
We probably spent the most amount of time on the eyes. We added the Paragon bump offset to the Iris, we switched the eyes to using SSSSS (screen space subsurface scattering) so they looked much more natural in the socket (Gears of War 4 did not use SSSSS on the eyes). We added a lot of additional eye geometry such as eye water, tear duct, and eye AO geometry, which much improved the realism. As a finishing touch, we added in a dynamic Iris Caustic system inspired by Jorge Jimenez and Javir von der Pahlen's GDC 2013 talk. The faces were also re-worked to have much more accurate bone and face structures, which helped the believability a lot.
Art Director Aryan Hanbeck: We really wanted to make a significant improvement on character faces from Gears of War 4. The very first few seconds of the game feature a very closeup shot of Kait's face waking up from her nightmare. We had a small strike team working on Kait’s face for most of the project and they used that close up shot as the proving ground to show progress. Every once in a while, we would see a big jump and would be happy with the results until we would find something else to improve. The nice thing was that as improvements were made to Kait, we would then be able to carry those changes over to the other characters, so the entire cast made a quality jump.